1. Field of the Invention
This invention relates to novel hydroxy-imino-substituted aminoacetonitriles having utility as intermediates in the preparation of substituted 2-aminopyrazine compounds, which in turn are intermediates in the preparation of insecticidal benzoylpyrazinylureas disclosed and claimed in Belgian Pat. No. 833,288 (Mar. 11, 1976).
Description of the Prior Art
One of the main methods of synthesizing pyrazine compounds is that of building up the pyrazine ring system from aliphatic components to form the carbon-nitrogen bonds. Compounds useful in this method include .alpha.-aminonitriles, .alpha.-aminocarbonyl compounds, .alpha., .beta.-dicarbonyl compounds, and .alpha.-halogenoketones.
In the prior art, Sharp et al., J. Chem. Soc., 932 (1951), describe the condensation of .alpha.- aminonitriles with oximinomethyl ketones to yield 3,5-disubstituted 2-aminopyrazine-1-oxides, which are then heated with sodium hydrosulphite to reduce the oxides to yield 3,5-disubstituted 2-aminopyrazines. This reference teaches that the efficiency of the general reaction is decreased by the replacement of alkyl with aryl groups.
In another reference, Taylor et al., J. Am. Chem. Soc. 95, 6407-6412 (1973), describe the condensation of .alpha.-aminocyanoacetamide with an oximinoketone, for example, oximinoacetophenone or oximinoacetone, in glacial acetic acid solution, to yield 2-amino-3-carbamoyl-5-substituted-pyrazine-1-oxides. The products are used in pteridine syntheses.
Taylor et al., J. Am. Chem. Soc. 90, 2424 (1968), describe the condensation of ethyl .alpha.-aminocyanoacetate with isonitrosoacetone (oximinoacetone) in glacial acetic acid, to yield 2-amino-3-carbethoxy-5-methylpyrazine-1-oxide. This product is also useful in the syntheses of pteridines.
Also in the prior art is Masaki et al., Bull, Chem. Soc. Japan, 36, 922 (1963), which discloses the reaction of .alpha.-halo oximes with amines. The product thereby obtained is reductively cyclized using Raney nickel catalyst to yield a piperazinone.
Also included in the prior art are Masaki et al., J. Org. Chem., 29, 3165 (1964), and Masaki et al., J. Org. Chem. 31, 4143 (1966), both of which references disclose the reaction of protected .alpha.-aminohydroxamic acid with an .alpha.-chloro oxime, followed by removal of the oxime and O-benzyl groups, and treatment with ammonia to yield aspergillic acid-type compounds.